In the past, a technology in which a plurality of projectors are used to project a plurality of images on a screen has been used. For example, a technology that displays a 3-dimensional image by projecting a plurality of parallax images or a technology that displays an image with high brightness by projecting the same images so that the images overlap one another has been known. Further, it is possible to perform display on a large screen by arranging and displaying a plurality of images.
In the image projection position adjustment apparatus described in Patent Document 1, test patterns with different colors are projected from two different projectors so that the patterns overlap one another. Then, an image of the two projected test patterns is picked up by a camera, and the projection position is adjusted on the basis of a change in color information in the picked-up image (e.g., paragraphs [0043] to [0061] and FIG. 5 of Patent Document 1).
Patent Document 1: Japanese Patent Application Laid-open No. 2014-10264